Lift truck



Sept. 4, 1962 F. P. HOPFELD 3,052,323

LIFT 'mucx Filed March 24, 1961 5 Sheets-Sheet 1 Inventor FRED P. HOPFELD 3g, li/fiamflfll umdpm aQ-HmrnegS P 1962 F. P. HOPFELD 3,052,323

Inventor FRED P. HoPFELD B5 fl-ktcrnegs Sept. 4, 1962 F. P. HOPFELD 3,052,323

LIFT TRUCK Fileds March 24, 1961 s Sheets-Sheet 4 2 1 287 SK m. 28! '27s 1 5- 4? 'L-"Bc:

275 \ZSI 211 Inventor FRED P. HOPFELD 32/ J ornegfi Sept. 4, 1962 F. P. HOPFELD LIFT TRUCK 5 Sheets-Sheet 5 Filed March 24, 1961 Inventor FRED P. HOPFELD United States Patent 3,052,323 LIFT TRUCK Fred P. Hopfeld, Elmwood Park, 11]., assignor to Grand Specialties Company, Chicago, Ill., a corporation of Illinois Filed Mar. 24, 1961, Ser. No. 98,054 30 Claims. (Cl. 187-40) This invention relates to a manually operable lift truck that is of such size as to be conveniently used in relatively small areas such as workshops, office buildings and the like.

A lift truck is one form of materials handling equipment, and such are commonly represented by the relatively small manual type that can be operated and propelled manually by one person. Lift trucks of this type are ordinarily equipped with a load carrying pallet that is arranged for vertical movement on upright frame structure. Various kinds of jacks, mechanical or hydraulic, are associated with the frame structure and so arranged as to enable a mechanical advantage to be exerted when moving the pallet in a load lifting direction on the frame structure.

In most instances heretofore, relatively small lift trucks of the foregoing kind have been constructed as an entire unit, which is to say that the parts are usually related in a permanent and fixed manner. The primary object of the present invention is to so construct a lift truck as to enable the same to be disassembled into sub-units that can be easily re-assembled into an operative structure when desired. The primary advantage of such construction is that the lift truck can be knocked down with the various sub-units arranged in a compact nested form that can be easily packed in a confined space such as the trunk of an automotive vehicle, or within limited space in the bed of a pick-up or delivery truck. Thus, under the present invention a lift truck can be independently transported in a disassembled, nested condition to and from the area where it is to be used in a re-assembled or operative condition. Such relationship greatly enhances the possible uses of a lift truck of the kind under consideration, since there is involved no rigid, permanent relationship that makes independent transportation of the lift truck awkward or cumbersome or which limits the lift truck to use at a particular site.

Specifically under the present invention, the foregoing advantage is accomplished by constructing the lift truck with a pallet unit that can be readily dis-associated from the frame structure, and a wheel unit that can be readily dis-associated from the frame structure, and such arrangement capable of dis-assembly into a frame unit, a pallet unit, and a wheel unit represents another object of the present invention. More specific objects of the present invention in this regard are: to enable the frame structure on which the pallet is guided to be removably set on wheel mounting means that are part of the wheel unit while enabling the wheel unit on the other hand to be locked to the frame structure in such a manner that these units will be integrated while at the same time capable of selected separation when desired; to permanently associate stabilizers with the wheel unit in such a manner that the wheel unit including the stabilizers will stably support the frame, but can be neatly nested with respect to the frame structure when these two sub-units are separated; and to so construct the pallet structure that it is merely necessary to in effect hang this on a lift bar guide in the frame unit when it is desired to relate the pallet in an operative manner to the lift truck.

The pallet is operated under the present invention by means including a hydraulic jack unit. Necessarily, such a unit includes an operating handle which normally must be disposed in position to be conveniently operated manually. In many circumstances of using a lift truck, relatively narrow working spaces are involved, and another object of the present invention is to enable the hydraulic unit including the operating handle to be swung to such a position that even when working in narrow spaces the hydraulic unit can be readily operated. Thus, when working at corner areas or in narrow closet or crib spaces, it often occurs that there is not enough room to enable a hydraulic pump handle on a lift truck to be effectively reciprocated, but under the present invention, the hydraulic unit including the handle can be swung by the handle to a point where an effective stroke can be accomplished.

In connection with the foregoing, it may here be mentioned that a lift truck is often tilted rearwardly in moving a load since this enables a guiding or caster effect to be more easily realized. With many lift trucks as heretofore constructed with a hydraulic unit, the pump handle usually drops limply backwards when the truck is tilted rearwardly. Another object of the present invention is to prevent such rearward limp movement of the pump handle when the lift truck is tilted, and to do this without having resort to any special retainer clip or the like on the frame structure for preventing such movement of the handle.

When a lift truck is tilted rearwardly as noted, the load may be of such magnitude as to represent a hazard. Accordingly, another object of the present invention is to removably arrange auxiliary support structure at the rear of the lift truck. Advantageously, this will be an auXiliary wheel support capable of free rolling with the lift truck in a rearward tilted position.

One of the primary uses of a lift truck of the kind under consideration is to transport loads up a stairway. In many constructions heretofore, this has entailed the cooperation of several persons. It has been proposed to facilitate such operations by associating a stair climber attachment with a lift truck. Under the present invention, a stair climber attachment is afforded for a lift truck and is of such construction as to give rugged support when tilting the lift truck rearward on the forward edge of a stair tread incidental to advancing the lift truck up over the stair riser. This can be done by one person. Another object of the invention in this regard is to so construct the stair climber attachment as to be capable of quick and easy attachment to the Wheel unit referred to above in keeping with the dis-assembling aspects of the present invention.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show preferred embodiments of the present invention and the principles thereof and what are now considered to be the best modes for applying these principles. Other embodiments of the invention embodying the same or equivalent principles maybe made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.

In the drawings:

FIG. 1 is a perspective view of a lift truck constructed in accordance with the present invention;

FIG. 2 is a perspective view of one kind of pallet that can be associated with the lift truck;

FIG. 3 is a fragmentary sectional view on an enlarged scale taken substantially on the line 3--3 of FIG. 1;

FIG. 4 is a fragmentary side elevation at the lower end of the lift truck adjacent the wheel unit;

FIG. 5 is a perspective view of the wheel unit WU disassociated from the frame FS Of the lift truck shown in FIG. 1;

FIG. 6 is a fragmentary perspective view, partly in section, showing details of the manner in which the pallet is associated with lift bar structure;

FIG. 7 is an enlarged sectional view of the hydraulic unit HU;

FIG. 8 is a sectional view of a portion of the frame structure including a pallet associated therewith;

FIGS. 9 and 10 are fragmentary sectional views on an enlarged scale showing details of the association between the lift bar structure and the pallet at respectively opposite ends;

FIG. 11 is a vertical sectional view taken substantially on the line 1111 of FIG. 8;

FIG. 12 is a perspective view of a lift truck constructed under the present invention including another kind of pallet PM and one form of auxiliary support structure AW associated with the wheel unit;

FIG. 13 is a fragmentary end elevation taken substantially on the line 1313 of FIG. 12;

FIGS. 14 and 15 are elevational views of the skid structure that can be alternatively associated with the wheel unit to facilitate stair climbing;

FIG. 16 is a sectional view taken substantially on the line 1616 of FIG. 15;

FIG. 17 is a sectional view on an enlarged scale showing the manner in which such a skid SK is to be removably related to the wheel unit;

FIG. 18 is a fragmentary perspective view on one side at the rear of the lift truck showing a stair climber skid in operative position;

FIG. 19 is a diagrammatic view illustrating the manner in which the lift truck of the present invention is constructed for ease in movement up a stair;

FIG. 20 is a perspective view similar to FIG. 18 illustrating another alternative attachment that can be associated with the wheel unit; and

FIG. 21 is a perspective view illustrating the lift truck of the present invention, in nested, knocked-down form.

General Arrangement of Parts The lift truck under the present invention is identified by reference character 30 in FIG. 1 of the drawings as inclusive of a general upright frame structure FS, the construction of which includes a pair of upright frame members 31 and 32. As will be described in detail hereinafter, the frame members 31 and 32 are rigidly interconnected by spacing elements, and the lower ends of the uprights 31 and 32 are removably related to a wheel unit WU, FIG. 1, whereby the wheel unit WU and the frame structure FS can be disassociated from one another for convenient storage and transportation of the truck 30 in disassembled form, as shown in FIG. 21.

The frame structure FS affords a guide for a lift pallet P, FIGS. 1 and 2, which is arranged for vertical up and down movement at the forward side of the frame structure. The pallet may be of different forms as will be described hereinafter, but in any event, the pallet includes a load supporting member which projects forwardly of the frame PS. The pallet, as will be described, is adapted to move between a lower most position wherein it is disposed at floor level, to a selected upper position on the frame determined primarily by the maximum stroke of a fluid operated piston included in hydraulic jack mechanlsm.

Thus, a hydraulic jack unit HU, FIG. 1, is disposed in a generally vertical position on the frame between the spaced uprights 31 and 32. This hydraulic unit is adapted to extend or relax a chain CH which has one end anchored to a fixed member of the frame structure and the other end connected to a part which moves with the pallet.

The hydraulic unit is so arranged, as will be described, that it can be swung from one side to the other at the rear of the frame structure. In other words, there is no fixed or permanent position for the hydraulic unit, and as a consequence the hydraulic unit can be operated from extreme left-hand or right-hand positions at the back of the lift truck incidental to moving the pallet. Such relation for the hydraulic unit also enables the operating handle to be nested practically flat against the frame structure when the lift truck is disassembled and nested as shown in FIG. 21. a

It will be appreciated that a lift truck of this kind is often tipped rearwardly incidental to expeditious handling of the load carried thereby. This is particularly true in those instances of heavy loads and where it is desired to in effect pull the truck up a stairway. In view of this, the wheel unit WU is so constructed as to enable support structure to be arranged at the rear side of the lift truck and which is adapted to support the Weight on the lift truck when the lift truck is tipped rearwardly as viewed in FIG. 12, or as shown in dotted lines in FIG. 19. Such structure may be inclusive of auxiliary wheels AW, FIG. 12, or straight stair climber skids SK, FIG. 19.

Referring to FIG. 21, the lift truck as a whole is so constructed as to be capable of disassembly into component units. Thus, the wheel unit WU, FIG. 21, is separated from the frame structure FS, and this also applies to the pallet PM which is of the form shown in FIG. 12. Further, the auxiliary wheels AW have been removed from the wheel unit WU. The parts as thus disassembled can be arranged in a nested stack and packed neatly within a confined space such as a packaging carton PC shown in dotted lines in FIG. 21. The nested stack can also be moved into the trunk of an automotive vehicle or a narrow space in the bed of a pick-up or delivery truck.

The Frame and Wheel Units As noted hereinabove, the frame structure FS includes a pair of upright members 31 and 32. These members are in the form of stampings, and each is of identical construction. Referring to FIG. 9, which includes a section of the right-hand upright 32 as viewed in FIG. 1, it will be noted that each upright is of general channel shape so as to have at one side a flat web portion 35 with a pair of inwardly bent front and rear elongated flanges 36 and 37 at the opposite ends thereof. Each such flange is formed with an inwardly bent end portion 36B and 37E.

As will be apparent from FIGS. 1, 8 and 9, the flanges 36 that are part of each upright member 31 and 32 are in a forwardly disposed position. These flanges are normally disposed in generally vertical planes, and flanges as thus disposed define a vertical guide track in the frame structure relative to which the pallet P is adapted to travel as will be explained in detail hereinafter.

The upright frame members 31 and 32 are in part spaced and rigidified by a handle structure 40, FIG. 1, which is inclusive of a pair of rearwardly curved connectors 41 and 42 having forward ends Welded to the upper ends of the upright members 31 and 32 and shaped to neatly merge therewith. The connectors 41 and 42 that are welded to the uprights 31 and 32 are in turn joined and connected by a transverse handle bar 45 having free ends outward of the connectors provided with rubber grips 45G of the usual kind. Advantageously, the handle bar 45 is welded to the upwardly and rearwardly disposed ends of the connectors 41 and 42.

The uprights 31 and 32 substantially at the medial extents thereof are joined by an intermediate spacer in the form of an angled and stamped plate 48, FIGS. 1 and 8. This plate extends transversely of the uprights 31 and 32, and the opposite ends thereof are welded to the inside faces :of the upright members that afford the main elements of the frame structure and the guide track identified above.

The lower ends of the upright members 31 and 32 are rigidly reinforced and .tied together by a transversely disposed multi-angular spacer plate 50, FIG. 8. Thus, the plate 50 includes a substantially upright portion 51, a rearwardly bent portion 52 substantially at right angles to the forward portion 51, then an upwardly inclined portion 53, and finally a rearwardly extended portion 54 that is substantially parallel to the intermediate port-ion 52 of the plate 58. The ends of the plate 50 are welded to the inside faces of the uprights 31 and 32.

The lowermost edges of the uprights 31 and 32 are inclined upwardly projecting in a rearward direction from the guide flanges 36 as indicated at 56 in FIG. 8, and a relatively narrow strengthening flange 57 is extended along each individual edge 56. Again referring to FIG. 8, the portions 51 and 52 of the spacer plate 50 embrace a vertically oriented slot 69 formed on the lower edge of each upright member 31 and '32 rearward of the inclined edge 56. These slots on the frame members 31 and 32 enable the frame structure F8 to rest on the Wheel unit as will hereinafter be described. Rearward of the slot 60, the lower edge of each upright member 31 and 32, FIG. 8, is inclined upwardly at 61. This facilitates rearward tipping of the lift truck as will be apparent from the descriptions hereinafter.

A triangular bracket 55, FIG. 8, is welded to the rear of each upright 31 and 32 at the lower end thereof. Each bracket includes an upwardly inclined leg 66 that is substantially coplanar with the inclined edge 61 at the bottom of each upright member. Each bracket 65 also includes a leg 67 which is disposed substantially at right angles to the lower portion of the flange 37 of the related upright 31 and 32. The free ends of the legs 66 and 67 of the bracket 65 are the elements that are welded to the flange 37 of the related upright frame member. The two brackets 65 thus provided adjacent the lower ends of the uprights 31 and 32 participate in load distribution as will be described hereinafter.

The lift truck of the present invention is to be manually propelled, and to this end the wheel unit WU is associated with the lower extremities of the frame structure PS. The wheel unit is detachably secured in place as has been noted.

The wheel unit WU, FIG. 1, includes a pair of wheels '70 and 71. Wheel mounting means inclusive of axle support structure is provided relative to which the wheels are free to rotate, and the frame structure FS normally reposes thereon so that the wheel unit supports the weight of the frame structure. To this end, the wheels 7 0 and 71 are associated with an axle housing 73, FIGS. 1 and 5, and an axle 75 for the wheels is passed therethrough. The axis 75 has free ends extended outward of the ends of the axle housing 73, and these free ends are disposed within a pair of wheel housings in the form of left and right-hand fender elements 78 and 79, FIGS. 1 and 5. The wheels 70 and 7-1 are rotatably mounted on the free ends of the axle 75 Within the fender elements 78 and 79.

Each fender element is of general triangular shape and includes a pair of spaced side plates or skirts 80 and 81, FIG. 3, the upper ends of which are joined by an integral arcualte web 82 whereby each fender element is substantially U-shaped in cross section. As will be noted in FIG. 1, the arcuate web 82 is normally in a horizontal position when the lift truck is upright. Each fender element is inclusive of a front plate or shield 85, FIG. 5, which is eifective to close ofl? the front end of the related fender and which also serves as a support as will here-inafter be described. The rear ends of the fenders are open as will be apparent in FIG. 1 and the related rear edges of the fender skirts dd and 81 are angled upwardly at 86, FIG. 1, to facilitate and permit rather extensive rearward tipping of the lift truck.

The fender elements 78 and 79 are accurately spaced a predetermined amount by the ends of the axle housing 73 which are secured to the inside plate 81 of each fender unit as shown in FIG. 5. Thus, the inside plates 81 of the fender elements are spaced one from another by the axle housing 73 welded thereto, and the spacing is such that the inside plate 81 of each fender will substantially abut the outside face of the related web 35, FIG. 3, of the related upright member 31 or 32. It will be recalled that the lower end of each upright member 31 and 32 is 6 slot-ted at 60 as shown in FIG. 8, and such slots are adapted to embrace and neatly fit on the upper portion of the axle housing 73 as will be apparent from FIGS. 1 and 4. In this manner, the fname structure is supported by the axle mounting means embodied in the wheel unit.

It will be noted in FIG. 5 that a tie member 30 spans the rear ends of the fenders 78 and 79. This tie member is in the form of a tube having open ends for reasons to be explained hereinafter. The ends of this tie member 90 are rigidly secured to the rearwardmost portion of each fender '78 and 79, and the parts are so dimensioned rand configured as to assure that when the parts are assembled, the tie member 90 will rest on the horizontal legs 65. The purpose of this will hereinafter be described.

When the frame structure FS has been set on the wheel unit WU as above described, these two units are to be rigidly locked together. Advantageously this is accomplished by screw means carried on each fender and adapted to be secured in a nut carried by the adjacent upright 31 or 32 of the frame structure. Referring to FIGS. 3 and 8, a boss 92 is secured to the inside face of the web 35 of each upright 31 and 32 adjacent the lower edge thereof. A nut 93, FiG. 3, is retained in each boss 92. A lock nut 93L is arranged on the crew 94 within the fender plates and 81. The web 35 of each upright is provided with an aperture, and aligned apertures in the related fender, FIG. 3, enable a screw 94 to be passed therethrough with the threaded portion thereof secured in the related nut 93. Each screw 94 has an enlarged knurled head 94H that is disposed outward of the outside fender plate 80 as shown in FIG. 3. Thus, assembling the two units FS and WU, the screws 94 carried by each fender are backed off to enable the fenders to be substantially abutted against the outer faces of the webs 35 of the uprights 31 and 32 so that the screw can be turned into the nut 93 in the related nut-holding boss 92. Thereafter the screws are run in until a rigid relationship has been established.

In order to stabilize the lift truck against forward tipping, a pair of stabilizer 98, FIGS. 1 and 5, are secured as by welding to the front plates of the fenders so as to project forwardly therefrom. The stabilizer arms 98 are generally triangular when viewed in elevation, and each includes a flat lower face adapted to engage the surface on which the wheels 7 0 and 7 1 are adapted to travel. The upper face 98U, FIG. 1, of each stabilizer arm is sloped upwardly from the narrow forward end thereof in the direction of the fender elements so that each stabilizer arm includes a relatively thick base where it is Welded to the related fender plate 85 to be supported thereby.

T he Lift Pallet and Related Lift Structure The lift pallet P, FIGS. 1 and 2, is inclusive of a flat, forwardly projecting plate 100 onto which. the load to be lifted will be moved when the pallet is in its lowermost position on the frame structure as will be described. In this position, the marginal outside portions M, FIG. 2, at the underside of the pallet plate 11th) will rest on the upper inclined surfaces 98U of the stabilizer arms 98. In this connection, it will be noted that the plate 100 111- cludes at the forward edge thereof a downwardly turned lip 100L. In the lowermost position of the pallet P, the lip 100 L will overhang the forwardmost edges of the stabilizer arms 98 so that the lower edge of the lip ltlllL will be at floor level. Consequently, the equipment to be transported can be moved onto the plate 100.

It is to be noted at this point that the lowermost extents =of the guide surfaces 36E, FIGS. 4, l2 and 21, of the flanges 36 on the uprights are so angled as to be substantially vertical when the lift truck is standing upright, while on the other hand the major extents of :the flanges 3d upward therefrom are inclined rearwardly out of vertical plane. Now, the support plate or platform 100 of the pallet P is angled to relative to the guidetrack of the frame structure so as to be substantially in a horizontal plane when the pallet is upward of the guide surfaces 3613 when the lift truck is standing upright. Conversely, then, when the platform is lowered on to the guide surfaces 36E, it tips downward below horizontal at the angle of the sloped surfaces 98U of the stabilizer arms 93, and this facilitates loading and unloading of the pallet at floor level. The same angular relations prevail with the modified pallet PM to be referred to hereinafter. In other words, when the plate 100 is in load receiving position, it is in an inclined plane parallel to the incline of the upper surfaces 98U of stabilizer arms 98.

The load supporting member of the pallet need not necessarily include a continuous plate as 100. Thus, referring to FIG. 12, the forwardly projecting load supporting element of the pallet PM may include fork arms and 106 interconnected by a back-up plate as will now be described in connection with the pallet P. In other words, FIG. 12 shows a modified construction wherein the lift truck is equipped with a modified pallet PM of bifurcated or fork type in contrast to the pallet P.

Referring now to FIG. 2, the pallet P includes a backup plate 107 that is integral with the load supporting plate 101). The back-up plate 197 is related to the frame FS so as to travel parallel to the guide surfaces 36 and 36E. These two plates of the pallet are angled so that the pallet support element will move in the planes above described when the lift truck is upright. The underside of the lift plate or platform 130 is strengthened by a pair of elongated triangular shaped arms 1% and 1119 that are welded thereto. Like elements will be used to strengthen the lift forks 105 and 106 as shown in FIG. 21. The arms 10S and 109 are so located at the underside of the load supporting member of the pallet as to lie adjacent the inside faces of the stabilizer arms 98 when the pallet is in its lowermost position on the frame structure FS.

A pair of vertically oriented pallet support arms 115, FIG. 2, are welded in spaced relation to the rear face of the back-up plate 107, and as an assurance to further strengthening, the lower ends thereof are welded to upwardly extending bent portions of the strengthening arms 103 and 109 at the rear face of the pallet back-up plate 107. Each of the arms at the upper end thereof near the upper edge of the back-up plate 107 is slotted to afford respective hook elements 1151-11 and 1151-12. These enable the pallet to be hung on a lift plate or bar, as will be described hereinafter, which is guided in the frame structure for vertical movement incidental to raising and lowering the pallet P. A like relationship is established for the modified pallet PM shown in FIGS. 12 and 21.

Reduced frictional movement of the pallet P relative to the guide flanges 36 is afforded by a pair of rollers and 121, FIG. 2. These rollers are journalled on pins supported at the rear of each of the strengthening arms 108 and 109 that are included in the pallet structure. As will be noted in FIG. 9, the rollers 120 and 121 are so positioned as to bear against the related flange as 36 associated with the upright 31 or 32 that is opposite the related roller 120 or 121. The rollers 120' and 121 have a width substantially that of each flange as 36 so as to have a generous bearing contact with respect thereto. Thus, when a load is on the pallet P, a moment is exerted on the plate 100 tending in effect to push the rollers 120 and 121 rearward against the vertical guide surfaces 36, and the wide rollers 120 and 121 serve to effect a large distribution of the resultant forces against the frame struc ture.

The pallet P is lifted by what amounts to bar structure 125, FIG. 6, that is inclusive of an angle plate 126 that extends transversely of the frame uprights. The bar structure 125 is to be guided by the inside surfaces of the flanges 36 at the forward portions of the uprights 31 and 32. To this end, the angle plate 126 is dimensioned to be somewhat shorter than the spacing between the inturned edges 36E, FIG. 9, of the uprights 31 and 32. A roller support in the form of a tubular spacer 128 is secured as by welding to the vertical flange. of the angle plate 126, FIGS. 6 and 9, so as to extend parallel there with transversely of the frame structure. It will be noted that the tubular spacer 123 is of greater length than the related angle plate 126, or in other words the ends of the tube 128 extend approximately to the inturned edges 36E of the uprights 31 and 32 as shown in FIG. 9. An axle 13% is disposed within the tube 128, and rollers 133 and 134, FIGS. 1, 9 and 10, are journalled on the ends of the axle 130 which project beyond the ends of the tube 128. The relationship is such that the rollers 133 and 134 are disposed within the channels of the uprights 31 and 32 in position to travel along the inner faces of the upright guide flanges 36.

Thus, the flanges 36 on the upright frame members 31 and 32 serve not only as guides for the pallet rollers 120 and 121, but also serve as guides for the rollers associated with the lift bar structure 125. Advantageously, the outwardly disposed faces of the rollers 133 and 134 are of brass, 1343, FIG. 9, to reduce friction should the roller 133 or 134 engage the inside face of the related web 35.

The hooks 115111 and 115112 that are included in the pallet are adapted to embrace the end portions of the tube 123 that extend beyond the ends of the angle plate 126, this relationship being shown particularly in FIGS. 9 and 10. The hook elements can be freely set on or removed from the lift bar structure to thereby removably associate the pallet P or PM with the frame structure FS.

SWhen secured to the lift bar structure 125, the pallet P (or PM) is to be clamped in place to establish a stable relationship. Referring to FIGS. 9 and 10, this is accomplished by a pair of clip arms and 141 which are pivotally anchored to the remote ends of the angle plate 126 by respective pins MOP and 1411 Each clip as 14%, FIGS. 6 and 10, includes an end portion adapted to engage the opposed surface at the top of the hoop as 1151-11 on the pallet P. In order to assure a proper holding position of the clamps or clips 140 and 141 with respect to the hook members of the pallet, tight friction on the clip is established by slotting the angle plate 126 inward of each end as at 1265, FIG. 9, and slightly bending upwardly a free portion 126B, FIG. 10, of the angle plate adjacent the slot therein. This will afford an edge which in effect will bite into each related clip when the same is turned to the pallet clamp position illustrated in FIGS. 6, 9 and 10. In this connection, each of the clips 14d and 141 at the end thereof opposite that enga-geable with a hook as 115H is slotted as at 1408, FIG. 6, so as to have some yieldability with respect to the upwardly bent portion as 126B on the angle plate that is to frictionally engage the related pallet clamp arm 140 or 1411. Advantageously, fixed clamping positions are positively maintained by a pin as 145, FIGS. 6, 9 and 10, that is passed downwardly through openings at the slotted end of each clip which are aligned with a like opening at the slotted end of the plate 126 just inward of the slot as 1268 therein.

The lift bar structure 125 is raised and lowered by the chain CH which is associated with a hydraulic jack unit as will be described below. It will be pointed out in this connection that the chain CH includes one end CH1, FIG. 8, anchored to the angle plate 126 by a nut and bolt attachment to which the lower end of the. chain is pinned. Advantageously, the lift bar structure at this point of attachment is strengthened and stiffened by an angle member which includes flange portions respectively welded to the angle plate 126 and the spacer tube 128.

The extent of downward movement of the lift bar structure 125 is limited by stops that are disposed in the path of movement of the guide rollers 133 and 134. The downward limit position of the lift bar is shown in FIG.

21. Referring now to FIG. 8, an angle bracket as 35B is securely fixed adjacent the lower end of the inside face of each upright web as 35 included as elements of the uprights 31 and 32. These brackets are so oriented that one of the fiat faces 35BF thereof represents a wedge spaced from the opposed inside surface of the related guide flange 36. The narrow or olwer ends of the resultant wedge spaces (FIG. 8) are of less width than the related guide rollers 133 and 134. Consequently, the downward extent of movement of the lift bar structure 125 is limited by the rollers 133 and 134 wedging between the slanted brackets as 35B and the opposed flanges on the uprights. The parts are dimensioned so that this occurs under cir cumstances where the lower surface of the pallet rests on the upper surfaces of the stabilizers 98.

The Hydraulic Unit As noted above, the lift bar structure 125 is arranged to be raised and lowered on the guide track of the frame structure by a hydraulic unit HU so constructed as to afford what amounts to a hydraulically operable jack that is inclusive of an output piston 16%, FIG. 1. The piston 169 carries at the upper or free end thereof a guide in the form of a sprocket 161 over which the chain CH is trained. As noted above, one end CH1, FIG. 8, of the chain is secured to the lift bar structure 125. The other end CH2, FIG. 8, of this chain is anchored to the frame structure. Specifically, such anchoring of the other end is attained by passing the chain downward through an opening in the transverse tie member 48, FIG. 8, and associating a nut 162 and bolt therewith as will be recognized in FIG. 8. In order to distribute the stress on the plate 48, a cross plate 163 is interposed between the under surface of the plate 48 and the nut 162 which is associated with the bolt that in turn is secured to the end CH2 of the chain CH.

The output piston 168 is centered in an output cylinder 155 which is arranged between the uprights 31 and 32 in a generally upright or vertical disposition. Admission of fluid under pressure into the cylinder 165, as will hereinafter be described, is effective to raise the piston 169 which in effect will extend the flexible connector represented by the chain CH. On the other hand, when the cylinder 165 is bled, as will be hereinafter described, piston 168 is free to move downward due to the weight of the pallet P, or the load thereon, and such is accompanied by relaxation of the flexible connector.

Under the present invention, the hydraulic jack means as an entire unit inclusive of the cylinder 165 can be swung to an out'of-the-way position about the axis of the cylinder 165. This is of advantage when working in close spaces or when the lift truck as a whole is to be disassembled and crated as shown in FIG. 21, or packed into the trunk of an automotive vehicle, these being illustrative of instances where the lift truck is to be knocked down from an assembled state and nested until it is to be used.

Thus, referring to FIG. 8, the upper end of the cylinder 165 is secured to a sleeve 167 which is retained for turning motion in a corresponding opening in the horizontal portion of the bracer plate 48. In this manner, the cylinder 165 is in part held in its predetermined ver tical position. The lower end of the cylinder 165 terminates at a point somewhat above the horizontal portion 52 of the frame bracer 51) that is located at the bottom thereof. A downwardly extending screw 170 is welded to the lower end of the cylinder 165 so as to be substantially coaxial therewith. A lock nut set 170N is threaded on to the screw 170. The screw 170- includes a reduced portion 170R, FIG. 8, which is extended into a vertically extending stub tube 173 which is centrally located on and welded to the vertical portion 51 of the bracer plate 50 that extends transversely between the upright members 31 and 32. The lowermost free end of the screw element 174 within the stub tube 173 is provided with a retainer collar C. A retainer pin 175 is passed through an opening in and at one side of the stub tube 173 so as to be within the path of possible movement of the collar 178C on the screw 170. Consequently, with the pin 175 in place in the stub structure 173, this pin is effective to prevent upward displacement of the cylinder 165 relative to the stub structure 173. By raising or lowering the lock nuts 178N, these are effective to allow adjustment of the slack on the chain CH. At the same time, however, the arrangement of parts permits the cylinder 165 to be turned relative to the stub support 173. Thus, the screw 178 secured to the cylinder 165 is free to turn in the stub 173 when the cylinder 165 is turned with its support 167 relative to the bracers 48 and 54 The hydraulic jack means is inclusive of a reservoir 1819, a fluid passageway block 181, an input cylinder 182 and related input piston 183, and a manually operable arm or handle 18d that is used to pump the piston 183 in a manner to be explained hereinafter.

The reservoir 188 is in the form of an elongated tanklike housing as will be evident in FIGS. 7 and 8, and a top plate 186 is secured thereto. A spacer 187 is interposed between and is welded to the top plate 186 and the cylinder 165. Thus, the reservoir 1811 is secured to the cylinder 165 as a unit. The lower end of the reservoir chamber 181) is welded to the upper forward portion of the fluid passageway block 181, and these parts are disposed substantially in a right-angular relationship with the passageway block 181 substantially in a horizontal position projecting rearwardly from the reservoir as will be apparent in FIGS. 7 and 8. A spacer 188, FIG. 7, is interposed between and welded to the adjacent surfaces of the block 181 and the cylinder 165.

Thus, it will be seen that with the cylinder 165 free to swing as noted above, the reservoir aand block 181 are also free to swing therewith. Swinging of this unit is accomplished by and through the handle 184 which is also used to impart power to the hydraulic jack or motor unit which is effective through the flexible connector associated therewith to raise and lower the pallet P on the frame structure P8.

In so mounting the handle 184, resort is first had to a pair of parallel disposed support links as 1%, FIG. 7, which are located between the reservoir 180 and the input cylinder 182. The links 190 are pivotally secured by pins 191 at the lower end thereof to opposite sides of the passageway block 181. Thus, the links as 190 are free to pivot relative to the block 181. The handle 184 is of tubular form as will be noted in FIG. 7. A bifurcated or U-shaped arm 193 is rigidly connected to the handle 184 at the lower end thereof. This arm 193 projects forwardly from the handle 184 in the direction of the reservoir 18%, and the forward end thereof is telescoped over the upper ends of the links 1%. Arm 193 is pivotally related by a pin 195 to the upper ends of the links 190. In this manner, the handle 1841 in effect is articulated to the base 181.

The rear or heel portion of the arm 193 that extends below the handle tube 184 is connected by a pin 196, FIG. 7, to the upper end of the input piston 183 that projects outward of the input cylinder 182. As a consequence, it will be seen that in imparting upward and downward strokes to the piston 183, the handle 184 is reciprocated along an arc, and advantageously a rubber handle grip 1846 is fitted on to the upper end of the handle 184. By exerting a side thrust on the handle 184 as distinguished from a pumping stroke thereof, the entire hydraulic jack unit including the cylinder 164 can be swung in an are as will be apparent from FIG. 11 of the drawings.

In order that the handle 184- will be disposed in an idle position substantially coaxial with the input cylinder 182 even at times when the lift truck is being tilted, means are associated with the handle 184 to be effective on the upper end of the piston 183 to maintain the handle 184 in the idle position as aforesaid. To this end, a biasing element or detent in the form of an elongated bar 2%, FIG. 7, is disposed within the tubular member 184; which affords the pump handle. This bar has a lower end 289L, FIG. 7, adapted to bear against the free upper end of the input piston 183. The detent 201 at the upper end ZtltlU thereof is engaged by one end of a coil spring 261 within the tube 184, and the coil spring 201 at the opposite or upper end engages a retainer pin 283, FIG. 7, which extends transversely of the pump handle 184. The parts are so related that the spring 201 is slightly compressed. As a consequence, the spring 281 is loaded and is effective to exert spring pressure downward on the bar or detent 288 so that it in turn is resiliently urged into contact with the upper end of the input piston 183. Because the detent 280 is yieldable, it will shift axially of the pump handle 18 1 when the latter is being reciprocated during operation of the hydraulic jack. Thus, the detent 208 will move with the pump handle 184% along an are when the pump handle is being operated, but the spring 281 prevents any binding between the upper end of the input piston and the lower end of the detent 200 as will be apparent from the dotted line showing in FIG. 7. At the same time, however, the spring detent arrangement including the parts 291)- and 201 will be effective normally to maintain the pump handle substantially in an upright position as shown in FIGS. 1 and 7 when the hydraulic unit is not being operated.

The input piston 183 moves in the cylinder 182. The

cylinder 182 extends vertically upward from the passageway base 181, and advantageously the cylinder 182 is reduced and threaded at the lower end 182T thereof so as to be capable of being threadedly mounted in a tapped opening in the passageway base 181. A seal washer 182W, FIG. 7, is interposed between the base 181 and the portion of the input cylinder 182 that is immediately upward of the threaded portion 182T thereof.

The input piston 183 operates in a bore 182B in the cylinder 182. Escape of fluid past the operating or lower end of the input piston 183 is prevented by seal means such as an O-ring 265 and resilient washer means 206, FIG. 7, that are retained in suitable grooves in the lower end portion of the input piston 183 that is disposed in the cylinder bore 182B. The lower end of the cylinder 182 is formed with an elongated passage 208 which extends from the lower end of the bore 182B to a chamber 2119 formed in the passageway base 281. The chamber 209 communicates through a restricted port 202T with a transverse passageway 211 in the base or block 211. The passageway 211 at the end opposite the port 289T communicates with a vertically upwardly extended passage 212, and this passage opens into the chamber 188C of the reservoir 18@ where the supply of hydraulic fluid is available.

Passageway 211 includes an enlarged portion 213 beneath the port 209T, and a check valve in the form of a ball 214 is seated therein. The passageway 211 is further enlarged at 215 outward of the ball 214, and a check valve in the form of a ball 216 is seated therein. The two seats 213 and 215 for the balls 214 and 216 are spaced as will be noted in FIG. 7, and a coil spring 220 is interposed between these two check valves.

The passageway 211 is further enlarged and is tapped at 211T outward of the ball 216 as shown in FIG. 7, and a plug 221 is threadedly mounted in the free end of the passageway 211. A coil spring 222 is effective between the inner threaded end of the plug 221 and the ball 216 to normally hold the latter against its seat 215, and in turn the ball 216 in its seat is effective through the spring 220 to hold the ball 214 normally in its seat. The parts are so dimensioned and oriented that the restricted port 269T is located between the two check valves 214 and 216, which is to say that the port 289T associated with chamber 209 is approximately centered with respect to the longitudinal dimension of the spring 229.

As a consequence of the foregoing arrangement, the input piston 183 on the upstroke thereof creates suction or reduced pressure in the passages 288, 2119 and the portion of the passageway 211 wherein the spring 228 is disposed. The suction or reduced pressure thus created is sufficient to in effect cause hydraulic fluid under atmospheric pressure in the oil chamber 180C to push the check valve 214 to the right as viewed in FIG. 7, causing the spring 200 to compress against ball 216. However, the pressure thus exerted on the spring 220 is not suflicient to move the ball 216 off its seat, because the spring 222 is selected as having a spring rate suflicient to resist this unseating tendency. Therefore, a supply of hydraulic fluid surges into the cylinder bore 182B, and on the normal pause of the handle 184 at the top of the stroke, ball 214, is seated in check position by spring 220 to seal off the reservoir.

On the downstroke of piston 183 in the cylinder bore 18213, the ball 214 is forcefully held by oil pressure against the seat 213 to seal off the portion of passageway 211 which leads to the oil reservoir chamber. At the same time, during the course of the downstroke of piston 183, ball 216 is unseated by the oil pressure and is moved to the right off its seat 215 as viewed in FIG. 7, causing compression of spring 222.

The enlarged portion of passageway 211, wherein the ball 216 and the spring 222 is disposed, communicates with a relatively short and angled port 225 which in turn communicates with an enlarged passageway 227 which extends along the bottom of the block 181 in the direction of hte output cylinder 165. The end of the passageway 227 opposite the port 225 opens at the face of the block 181 opposite the plug 221. A communicating port 230 is formed in the spacer block 188, and this port in turn communicates with a port 231 formed in the lower end of the cylinder 165 where it abuts the spacer 188.

It will therefore be seen that on the downstroke of the piston 183, fluid under pressure is forced into passageway 227 and through ports 230 and 231 to surge into the lower end of the output cylinder 165. Pressure is therefore created on the lower or operating end of the piston 16% in the cylinder 165, causing upward movement of the piston 160. Repeated strokes of the pump handle 184, therefore, raises the output piston stepwise causing the connector CH to be extended as the guide 161 is raised with the piston. Consequently, the lift pallet ist raised in a stepwise fashion to the desired height.

The fluid seal, in effect, for the output cylinder and piston is afforded in the sleeve 167. Thus, the upper end of the cylinder 165 is telescoped tightly into a recess 167R at the underside of the sleeve 167, FIG. 7, and these parts are secured and sealed by an annular braze BR. An annular ring 233 within the sleeve 167 closely embraces the piston 160. The interior of the sleeve 167 upward of the ring 233, FIG. 7, is enlarged 1n diameter to afford a generous space surrounding the portion of the piston 169 coextensive therewith. A retainer snap ring 234 is fitted into a groove at the upper end of the sleeve 167, and fluid-tight ring seal packing is arranged between the rings 233 and 234 to prevent escape of operating fluid from the cylinder 165.

By bleeding the output cylinder, that is, draining it to the reservoir, the fiexible connector that is extended between the frame structure and the lift pallet is adapted to be relaxed to permit the pallet to lower. This can be a restricted effect for slow lowering of the pallet, or a wide open effect for more rapid lowering of the pallet. This will depend primarily on the nature of the load, if any, on the load supporting portion of the pallet.

Referring now to FIG. 7, the block 181 is formed with an upwardly extending port 246' that communicates with the transfer passage 227. The upper end of the port 240 communicates with an angular seat 241 on which a check valve ball 242 is normally seated. The ball 242 is disposed for movement in a chamber 245, and an angular passage 246 extends upwardly therefrom and opens at the upper face of block 181 to communicate with the oil chamber 180C.

The upper face of block 181 is formed with a tapped opening 247. The threaded end of a retainer and regulating rod 250 is formed at the lower end thereof with a smooth, reduced portion 251 that is disposed in the chamber 245 in which the check ball 242 is located. The end portion 251 of the rod 251} will retain the ball in the chamber 245, but it should also be noted at this point that the displacement between the ball 242 in its seat and the end 251 of the rod 250 determines the rate at which cylinder 165 can be drained when allowing the pallet P or PM to move downward on the frame.

The retainer rod 250 extends upwardly of and within the oil reservoir 231). The upper end thereof is connected by a pin 252 to the recessed lowerend of an adjuster knob 255. The adjuster knob extends outwardly of the top plate 186 of the oil reservoir 181) and is provided with a knurled head 258. A guide or support sleeve 260 is secured to the top plate 186 so as to extend. downwardly within the oil reservoir 18%), and the adjuster stub portion of the adjuster knob 255 is disposed therein for turning movement. An O-ring seal 262 is seated in a grooved portion of the adjuster 255 that is disposed in the sleeve 260 so as to effect a seal therebetween. It will be seen that by turning the knurled head 258 clockwise or counterclockwise, the reduced end 251 of the retainer rod 250 can be moved toward or away from the check ball 242. This determines the rate at which the output cylinder can be bled or drained as will be explained.

In order to assist in assuring that the ball 242 can be seated properly during assembly of the hydraulic unit, and to facilitate removal and replacement of the ball 242, an elongated guide sleeve 265, FIG. 7, has the upper end thereof press-fitted on to the lower end of the adjuster knob 255 that projects below the guide sleeve 260 in the reservoir chamber. The lower end of the tube 265 fits flush against the upper surface of the block 181. Consequently, by withdrawing the retainer 250 with respect to the oil reservoir, the ball 242 can be removed by tilting the oil reservoir 180, and by the same token a new ball can be dropped accurately in place down the tube 265. Advantageously, the tube 265 is provided with a plurality of ports 2651 so that there can be free flow of hydraulic fluid therethrough.

It will be recognized that the check ball 242 permits fluid to flow between the oil reservoir and the elongated passage 227. Thus, unless the ball 242 is tightly held down in blocking position over the upper end of the port 241, fluid under pressure in the passageway 227 can flow to the oil reservoir when the input piston 183 is driven downward in the input cylinder 132. Normally, the ball will be held so seated, but in any event cylinder 165 can be drained or bled by backing off the retainer rod 251) with respect to the check valve ball 242. When this is done, the weight of the pallet, or the load thereon, acting on the flexible connector that is secured to the guide 161 on the output piston, will cause the latter to be forced downward in the cylinder 165, and the rate at which this occurs can be regulated by the amount of displacement established between the free reduced lower end 251 of the retainer 251} and the ball 242. The rate of descent permissible will depend primarily upon the type of load supported by the pallet. As noted above, the extent of downward movement of the pallet as P or PM is limited by the guide rollers 133 and 134 eventually seating on the brackets as 35B, FIG. 8.

Auxiliary Suppport Structure It will be recalled that a support and bracing tube 90, FIGS. 1, 4 and 5, extends transversely of and is secured to the rear end portions of the fender elements 78 and 79. This tube normally rests on the leg portions 67, FIG. 8, of the angular brackets 65 which project rearwardly and which are secured to the uprights 31 and 32.

The support 94 has open ends as will be paraticularly apparent from FIGS. 1 and 4. This enables auxiliary support structure to be removably associated with the wheel unit. Such may include auxiliary wheels AW, FIG. 12, or planar stair climber skids as SK, FIGS. 18 and 19.

Thus, referring to Flu. 12, four points of support can be afforded for the lift truck when it is tilted rearwardly, and such four points of suspension will include the two main wheels 7d and '71 and the two auxiliary wheels AW. Such support enables heavy loads in particular to be easily transported. The auxiliary wheels are rotatably supported on individual stub axles 271 and 272, FIG. 13, which are removably retained within the support tube 91) by releasable spring clips as will hereinafter be described in connection with the stair climber skids SK. In other words, the support tube 9h in the modification of the invention illustrated in FlGS. l2 and 13, serves as an axle support for the auxiliary wheels AW. The auxiliary wheels AW not only serve to effect a wide distribution of the load on the floor when the lift truck is tilted in the manner illustrated in FIG. 12, but can also be used to facilitate stair climbing as will be apparent from the description to follow in connection with the stair climber attachment skids SK.

Lift trucks of the kind under consideration are commonly employed to facilitate movement of material or equipment between floor levels. This of course entails in many instances the need for gradually moving the lift truck up a stair incline as illustrated in FIG. 19. Under the present invention, such movements are facilitated by providing a pair of stair tread-engaging elements in the form of skids SK, FIGS. 18 and 19 which can be removably attached and supported primarily at the opposite ends of the tube 90.

Referring to FIGS. 14, 15 and 16, each skid is formed from a one-piece angle plate 275 which is inclusive of a pair of flanges 276 and 277 substantially at right angles to one another. The dimensions are such that the skids will not interfere with normal use of the lift truck being moved continuously about a horizontal surface. To this end, the flange 277 which is included in each of the skids is to extend upwardly at the outside of each fender element approximately at the angle of the rearward incline as 86, FIG. 1, at the underside of the fender plates. Consequently, the skids do not present edges or surfaces that will interfere with normal manipulation of the lift truck. Further in this connection, each skid, during formation, is cut by a torch or the like straight inward from the bend line at the remote ends of the angle 275 where the flanges 276 and 277 merge at a right angle bend. Having thus-formed slots, the freed end portions of the flange as 277, FIG. 14, are then bent slightly upward at 280 and 281. After thus being bent, weld deposits W1 and W2, FIGS. 14 and 15, are then applied to integrate the rigid incline portions 280 and 281 of the skid to the flange 276, the surplus triangular portions of the latter (indicated by dotted lines E1 and E2, FIG. 14) being removed.

Each skid is inclusive of a stub tube 285, FIGS. 15 and 16, that is welded to the face of the flange .276 opposite from which the flange 277 projects. As shown in FIG. 16, each stub 285 is disposed approximately at right angles to the adjacent face of the related skid flange 276. Advantageously, each stub 285 is secured in place by disposing the same in a corresponding opening in the flange 276 and thereafter providing a joining weld thereabout.

Each skid is inclusive of a hook element 287 of bent 155' rod form, FIGS. 14 and 15, having one leg thereof welded to the same face of the flange 276 from which the tube stub 285 projects. Each rod 287 is formed with a bent portion 287 at the free or unwelded end thereof, and this bent portion is adapted to be disposed in an opening 2%, FIG. 12, on the related fender element.

As shown in FIG. 15, a spring clip 295 is disposed in each stub as 285. This spring includes a coiled portion 295C, FIG. 17. A pair of parallel legs 2% and 297 extend forward from the coiled portion of the spring 295. Each leg includes at the free end thereof a bent extension 296E and 297E and these bent portions are disposed in a pair of corresponding apertures, FIG. 17, formed at diametrically opposite points in the portion of the stub 285 that lies adjacent the flange 276 of the related skid SK. The bent end 296E of each spring 295 projects outward of its related apertures in the related stub 285. However, the other bent end 297E is finished off to be flush with the outer surface of stub 285.

In securing the stair climber skids SK in position on the wheel unit WU, the exposed end 296E of each spring 295 that is disposed in the stub 285 of each skid is depressed by a screwdriver or the like so that this end of the spring 295 will be flush with the outer surface of the stub sleeve 285. Having established this condition, the stub 285 is then inserted into the support tube 99 at one of the open ends thereof, and once the depressed end 296E of the spring 295 is within the tube 90, the related skid SK is then turned so that the end 2373 of the hook rod 257 will be aligned with the receiving opening 29%) afforded therefor in the related fender as 78, FIG. 12. The skid is then pressed home so that the bent end 287B of the hook rod 287 fits into the aforesaid opening 290, and the parts are so dimensioned that when the proper position has been attained the end 296E of the spring arm 2% springs into a receiving opening 961, FIG. 17, that is afforded therefor at one end of the tube 9Q. Each skid SK is, of course, positioned and related to the wheel unit in this manner.

Referring to FIG. 19, the skids SK in operative position afford a sturdy inclined support at each side of the rear of the wheel unit WU. When the skids are in this operative position, the upwardly and forwardly bent ends 281 of the skid flanges 277 are disposed in planes above the plane in which the main wheels 7 (l and 71 are disposed. Additionally, the flanges 277 under such circumstances are so inclined rearwardly and upwardly as to be engageable with the forward edge of a stair tread ST as shown in FIG. 19 with the wheels 70 and 71 somewhat forward of the stair riser SR. When so disposed, the flange portions 277 of the skids SK, bearing against the edge of the stair tread ST, afford a fulcrum on which the lift truck can be tilted rearwardly and pulled upwardly over the stair riser to bring the wheels 70 and 71 on to the next stair tread ST. Advantageously, the skids SK are so dimensioned that the rearwardly and upwardly bent portions 282 of the flanges 277, as the lift truck is being moved on to a new stair tread, will engage the next stair tread STN as shown in FIG. 19.

Summary It will 'be seen from the foregoing that under the present invention a lift truck is constructed in such a manner as to enable the same to be easily disassembled into separate units inclusive of a frame unit, a wheel unit on which the frame rests, and a pallet unit to be cantilevered on the frame. When so disassembled, the units can be easily nested in a compact manner as illustrated in FIG. 21 for the purposes explained above.

The frame supports a hydraulic jack unit that is so mounted on the frame as to be capable of pivotal movement about the axis of the output cylinder (substantially parallel to the longitudinal axis of the frame to positions where the pump handle is quite close to the frame so that the hydrauli? unit can be operated even though narrow or confining spaces are encountered. In this connection it will be recalled that the pump handle has a spring retainer associated therewith that is effective, when the pump handle is idle, to bias the pump handle substantially to an upright position so that it will not drop rearward to an interfering position when the lift truck is tilted rearwardly. This is so even though the pump handle is articulated on the hydraulic unit for reciprocation in an arcuate path.

The wheel unit is readily separable from the frame structure merely by backing off the locking screws having the heads 94H, FIGS. 1 and 5. When this has been accomplished, the frame structure and the pallet unit P or PM can be separated unitarily from the wheel unit, although under most circumstances the pallet P or PM will be removed from the frame structure before effecting a separation between the frame unit and the wheel unit.

The wheel unit has forwardly directed, floor-engaging stabilizer arms 98 rigidly associated therewith as a part of the wheel unit. Auxiliary supports as wheels AW or stair skids SK can be removably related to the rear of the wheel unit.

The pallet is readily separable from the frame unit merely by turning the retainer clips as 140 and 141 to a releasing position, whereafter it is merely necessary to lift the pallet to disengage the hook elements 115Hf and 1151-12 thereof from the lift bar structure 125.

It will be realized that the loaded pallet exerts a moment on the frame FS tending to pivot the frame forwardly about the wheel unit. However, the major component of this moment will be exerted by the brackets 65 on the tube of the wheel unit.

Hence, while preferred embodiments of my invention have been illustrated and described, it is to be understood that these are capable of variation and modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

1. In a lift truck, laterally spaced upright members affording a vertically disposed frame and guide track, a vertically movable lift bar guidably mounted transversely of and between the upright members, a wheel unit including wheels and forwardly projecting stabilizer means adapted to repose at floor level, said wheel unit being removably secured to the frame at the lower end thereof, jack means associated with the frame, a connector be.- tween the jack means and the lift bar and adapted to be extended and relaxed by the jack means to raise and lower the bar relative to the upright members, and a lift pallet removably attached to the lift bar and including a load bearing member projecting forwardly from the frame.

2. In a lift truck, laterally spaced upright members affording a vertically disposed frame, each of said upright members having a flange defining a guide track, a vertically movable bar having rollers at the opposite ends thereof each in engagement with one side of a related one of the flanges, jack means associated with the frame, a connector between the jack means and the bar and adapted to be extended and rel-axed by the jack means to raise and lower the bar relative to the upright members, a lift pallet cantilevered on and removably attached to the bar and including a load bearing member projecting forwardly from the frame, said pallet having spaced rollers thereon each in engagement with the side of a related one of the flanges opposite that side engaged by the roller on the bar, and a wheel unit including a pair of stabilizer arms and a pair of wheels removably secured to the upright members.

3. A lift truck according to claim 2 wherein the lift pallet includes hook members rigidly secured thereto and which freely embrace said bar to removably mount the lift pallet on the bar.

4. In a lift truck, laterally spaced upright members affording a vertically disposed frame and guide track, a vertically movable lift pallet guidably mounted transversely of and between the upright members, wheels associated with the frame enabling the lift truck to be manually propelled, hydraulic jack means carried by the frame and including a vertically disposed cylinder and piston, manually operable hydraulic means for raising and lowering the piston in said cylinder, connections between the piston and the pallet enabling the pallet to be raised and lowered therewith, and said manually operable means being mounted on the frame for swinging motion about the axis of said cylinder.

5. A lift truck according to claim 4 wherein the wheels are part of a separable wheel unit including a pair of fender elements relative to which the wheels are rotatable, a tie member interconnecting the fender elements and spacing the same by an amount which disposes the fender elements substantially in abutting relation to the upright members, said upright members reposing freely on said fender tie member, and means for remova'bly securing the fender elements to the respective upright members.

6. A lift truck according to claim 5 wherein each of the fender elements includes a forwardly projecting floorengaging stabilizer arm.

7. In a lift truck, laterally spaced upright members affording a vertically disposed frame and guide track, a vertically movable bar guidably mounted transversely of and between the upright members, hydraulic jack means associated with the frame, a flexible connector between the jack means and the bar and adapted to be extended and relaxed by the jack means to raise and lower the bar relative to the upright members, a lift pallet having elements thereon removably intenfitted with the bar and enabling the pallet to be detached with respect to the frame, and a removable wheel unit at the bottom of the frame, said wheel unit including wheels and wheel mounting means relative to which the wheels are free to turn, said upright members having portions at the lower end thereof removably set on the wheel mounting means, and means removably securing the wheel mounting means to the frame.

8. A lift truck according to claim 7 wherein the hydraulic jack means is free to be swung manually to an out-of-the-way position about an axis substantially parallel to the longitudinal axis of the frame.

9. A lift truck according to claim 7 wherein the wheel mounting means includes a pair of fender elements housing the wheels, and wherein stabilizer arms are secured to and project forwardly from the fender elements in position to engage the surface on which the wheels will roll.

10. A lift truck according to claim 9 wherein the fender elements are provided with screws seated in nuts secured to the upright members to removably secure the fender elements to the frame, and wherein the wheel mounting means includes an axle housing and tie member secured to the fender elements, an axle for the wheels being disposed in said axle housing, and the lower ends of the upright members being slotted to embrace the axle housing.

11. In a lift truck, laterally spaced upright members affording part of a vertical frame structure and guide, a vertically movable lift bar guidably mounted transversely between the upright members, a lift pallet supported "by the lift bar, wheels associated with the frame enabling the lift truck to be manually propelled, hydraulic jack means arranged between the frame members and including an output cylinder and a piston therein disposed in a generally upright position, said piston having a guide at the upper free end thereof projecting outward of the cylinder, at flexible connector secured at one end to the frame structure and secured at the other end to the lift bar, said output cylinder being pivotally supported in the 18 frame structure for selected swinging movement about its vertical axis, said hydraulic jack means including a hydraulic reservoir and input piston and cylinder as a unitary body secured to the first-named cylinder to swing therewith, a manually operable arm for pumping the input piston to furnish fluid under pressure from the reservoir to the output cylinder, and said arm being connected to one of the members comprising the hydraulic jack means to enable the output cylinder to be swung by said arm.

12. A lift truck according to claim ll wherein said arm is pivotally connected to the input piston and includes a spring detent bearing on the input piston tohold the arm normally in a position generally aligned with the longitudinal axis of the frame irrespective of rearward tipping of the lift truck,

13. In a lift truck, laterally spaced upright members arrording part of a vertical frame structure, said upright members each having a flange extending for substantially the full length thereof and having an inside and outside face in substantially parallel vertical planes, a vertically movable bar disposed transversely between the upright members, said bars having a roller at each end thereof in rolling contact with the inside face of the flange on a related upright member to travel therealong, a lift pallet removably supported by the bar, said lift pallet having a pair of rollers carried thereby and each being in rolling contact with the outside face of the flange on a related upright member to travel therealong, wheels associated with the frame enabling the lift truck to be manually propelled, hydraulic jack means arranged between the frame members and including an output cylinder and a piston therein disposed in a generally upright position, said piston having a guide at the upper free end thereof projecting outward of the cylinder, a flexible connector secured at one end to the frame structure and secured at the other end to the lift bar, said output cylinder being pivotally supported in the frame structure for selected swinging movement about its vertical axis, said hydraulic jack means including a hydraulic reservoir and input piston and cylinder unit secured to the first-named cylinder to swing therewith, a manually operable arm for pumping the input piston to furnish fluid under pressure from the reservoir to the output cylinder, and said arm being connected to one of the members comprising the hydraulic jack means to enable the output cylinder to be swung thereby as aforesaid.

14. A lift truck according to claim 13 wherein the rollers on the pallet are wider than the rollers on the bar.

l5. A lift truck according to claim 13 wherein the pallet is provided with hook elements that embrace the bar to removably mount the pallet on the bar, and wherein manually releasable clamps are effective between the pallet and the bar to hold the pallet in place on the bar.

16. In a lift truck, laterally spaced upright members affording part of a vertical frame structure and guide, a lift pallet associated with said guide to move with respect thereto, hydraulic jack means arranged between the frame members and including an output cylinder and a piston therein disposed in a generally upright position, said piston having a guide at the upper free end thereof projecting outward of the cylinder, a flexible connector anchored at one end to the frame structure and arranged at the other end to effect raising and lowering of the pallet depending upon the direction of the stroke of said output piston, said output cylinder being pivotally supported in the frame structure for selected swinging movement about its vertical axis, said hydraulic jack means including a hydraulic reservoir and input piston and cylinder unit secured to the first-named cylinder to swing therewith, a manually operable arm for pumping the input piston to furnish fluid under pressure from the reservoir to the output cylinder, said arm being connected to one of the members comprising the hydraulic jack means to enable the output cylinder to be swung as aforesaid, and a separable wheel unit supporting the frame, said wheel unit including wheels and fender elements therefor interconnected by a tie member relative to which the wheels are free to turn, the lower ends of said upright members resting on the fender tie member, and said fender elements being removably connected to the lower end of said frame.

17. A lift truck according to claim 16 wherein stabilizer arms are secured to the fender elements and project forwardly therefrom, an elongated tie member spanning and connected to the rear ends of the fender elements, and supports removably mounted on the ends of said elongated tie member for supporting the lift truck when the lift truck is tipped rearward.

18. In a lift truck, laterally spaced upright members affording part of a vertical frame structure and guide, a vertically movable lift pallet guidably mounted transversely between the upright members, wheels associated with the frame enabling the lift truck to be manually propelled, a hydraulic jack unit arranged between the frame members and including an output cylinder and a piston therein disposed in a generally upright position, said piston having a guide at the upper free end thereof projecting outward of the cylinder, a flexible connector of predetermined length secured at one end to the frame structure and secured at the other end to effect raising and lowering of the pallet depending upon the direction of the stroke of said output piston, said output cylinder being supported in the frame structure for selected swinging movement about its vertical axis to an out-of-the-way position, and for selected vertical adjustment to regulate the slack on the connector, said hydraulic jack unit including a hydraulic reservoir and an input piston and cylinder secured to the first-named cylinder to swing therewith, and a manually operable arm pivotally mounted on the hydraulic unit for pumping the input piston to furnish fluid under pressure from the reservoir to the output cylinder and for enabling the output cylinder to be swung as aforesaid.

19. In a lift truck, laterally spaced upright members affording part of a vertical frame structure and guide, a vertically movable lift pallet guidably mounted transversely between the upright members, wheels associated with the frame enabling the lift truck to be manually propelled, a hydraulic jack unit arranged between the frame members and including an output cylinder and a piston therein disposed in a generally upright position, said piston having a guide at the upper free end thereof projecting outward of the cylinder, a flexible connector secured at one end to the frame structure and secured at the other end to effect raising and lowering of the pallet depending upon the direction of the stroke of said output piston, said output cylinder being pivotally supported in the frame structure for selected swinging movement about its vertical axis to an out-of-the-way position, said hydraulic jack unit including a hydraulic reservoir and an input piston and cylinder secured to the first-named cylinder to swing therewith, and a manually operable arm for pumping the input piston to furnish fluid under pressure from the reservoir to the output cylinder and for enabling the output cylinder to be swung as aforesaid.

20. In a lift truck, upright members affording a vertically disposed frame and guide track, cross tie means rigidly bracing the frame and spacing the frame members laterally by a predetermined amount, a vertically movable lift pallet guidably mounted transversely of the upright members, manually operable means on the frame for raising and lowering the lift pallet, a separate wheel unit comprising wheel mounting means and an axle supported thereby, wheels on the axle, said upright members having portions freely resting on the wheel mounting means so that the wheel unit bears the weight thereof, and means removably joining the wheel unit to said frame.

21. In a lift truck, upright members affording a vertically disposed frame and guide track, cross tie members rigidly bracing the frame and spacing the frame members laterally by a predetermined amount, a vertically movable lift pallet guidably mounted transversely of and between the upright members, manually operable means on the frame for raising and lowering the lift pallet, and a separate wheel unit comprising a pair of spaced fender elements interconnected by a hollow member, an axle extended through said hollow tie member, wheels on the axle and housed in said fender elements, said upright members having portions freely resting on said hollow tie member so that the wheel unit bears the weight thereof, and means removably joining the fender elements to respective ones of said upright members.

22. A lift truck according to claim 21 wherein the fender elements are each joined to the related upright member by a screw secured in a nut fixed to the related upright member.

23. A lifht truck according to claim 22 wherein an auxiliary tie member is secured to the rear ends of the fender elements, and said upright members of the frame having projections at the rear thereof engaging said auxiliary tie member.

24. In a lift truck, a pair of laterally spaced upright members affording part of a frame structure, a pallet arranged for vertical up and down movement on the frame structure, wheels associated with the frame structure to enable the lift truck to be manually propelled, fenders for said wheels secured to the upright members, and said fenders being rigidly interconnected at the rear ends thereof by a transverse tie member having ends serving as mounting elements for supports which support the lift truck when tipped rearward.

25. A lift truck according to claim 24 wherein a pair of axles having wheels thereon are supported by the ends of said transverse tie member.

26. A lift truck according to claim 24 wherein a pair of stair climber skids having planar stair tread engaging flanges are attached to the ends of said transverse tie member.

27. A lift truck according to claim 24 wherein the transverse tie member reposes on projections secured to the frame structure.

28. In a lift truck, a pair of laterally spaced upright members affording part of a frame structure, wheels associated with the frame structure to enable the lift truck to be manually propelled, fenders for said wheels secured to the upright members, said fenders being rigidly interconnected at the rear ends thereof by a transverse tie member having ends serving as mounting elements for supports which support the lift truck when tipped rearward, and supports in the form of a pair of stair climber skids having planar surfaces adapted to engage the edge of a stair tread, the planar surfaces of said skids being upwardly and rearwardly inclined, and each of said skids having portions removably attached to the related one of said fenders and a related end of the transverse tie member.

29. In a lift truck, a pair of laterally spaced upright members affording part of a frame structure, wheels associated with the frame structure to enable the lift truck to be manually propelled, spaced wheel mounting elements for said wheels secured to the upright members, said wheel mounting elements being rigidly interconnected by a transverse tie member having ends serving as mounting elements for spaced supports which support the lift truck when tipped rearward, and spaced supports at the rear of the frame having solid surfaces normally in a plane above the plane of said wheels, each of said supports having portions thereon removably secured to a related one of the wheel mountin g elements and a related end of the transverse tie member.

30. In a lift truck, means affording an upright frame,

a load supporting member guided on the frame for vertical up and down movement, and hydraulic apparatus including an output cylinder and piston therein for controlling up and down movement of the pallet, said output cylinder being supported in the frame for turning movement about its own axis, said hydraulic apparatus further including a reservoir and input cylinder and piston unit connected to said output cylinder piston, block means connected to the reservoir and including passages interconnecting the cylinders and the reservoir, and an arm for reciprocating the input piston and connected to a member of said hydraulic apparatus to enable the hydraulic unit as a Whole to be swung about the axis of the output cylinder.

References Cited in the file of this patent UNITED STATES PATENTS Spaeth June 30, 1925 Reinert Feb. 11, 1947 Zenko July 11, 1950 Sasgen et a1. July 10, 1951 Bayer et a1. June 14, 1955 Pappathatos et a1 Mar. 19, 1957 Hopfeld May 12, 1959 Hopfeld Nov. 8, 1960 FOREIGN PATENTS Germany Apr. 11, 1957 

